Outboard motor



April 3, 1951 E. c. KIEKHAEFER OUTBOARD MOTOR Filed July 29, 1948 2 Sheets-Sheet l April 3, 1951 E. C. K IEKHAEFER OUTBOARD MOTOR 2 Sheets-Sheet 2 jaw .w/W

age always.

Filed July 29, 1948 Patented Apr. 3 1951 OUTBOARD MOTOR Elmer Carl Kiekhaefer, Cedarburg, Wis.

Application July 29, 1948, Serial No. 41,261

Claims.

This invention relates to outboard motors and particularly to an improved construction thereof.

A principal object of the invention is to provide an opposed two or four cylinder outboard motor employing identical component parts for each pair of cylinder which are interchangeable with those employed in a comparable non-opposed two cylinder engine of similar design.

Afurther object of the invention is to provide an outboard motor employing identical cylinder blocks for multiple pistons in opposed relation so that only a single casting, machine set-up and stock reserve is required for the same and for various other parts associated therewith.

Another object is to provide an outboard motor having opposed cylinders which exhaust from the respective cylinder blocks directly into the drive shaft housing without intermediate parts thereby reducing the cost of the completed motor.

Another object is to provide an outboard motor drive shaft housing which may be bolted directly to the off-set cylinder blocks of the engine to support the engineand receive the exhaust from the blocks directly into the expansion chamber of the housing.

These and other objects and advantages will be more fully set forth in the following description of a preferred embodiment of the invention illustrated in the accompanying drawings.

In the drawings:

Figure 1 is a side elevation of the engine and upper portion of an outboard motor with parts broken away and sectioned to show the construction thereof;

Fig. 2 is a side elevation of the complete outboard motor;

Fig. 3 is a side elevation of the upper part of a two cylinder alternate firing engine comparable to the engine shown in Fig. 1 and with parts broken away and sectioned;

Fig. 4 is a perspective view of the upper part of the housing member supporting the motor shown in Figs. 1 and 2; and

Fig. 5 is a perspective view of the upper part of the housing member supporting the engine shown in Fig. 3.

The outboard motor shown in the drawings includes the engine I, the drive shaft 2 and the hollow cast housing 3 therefor extending downwardly from the engine. The gear case 4 secured to the lower end of housing 3 carries the propeller 5 which is driven by engine I throughdrive shaft 2 and the bevel gears not shown enclosed within housing 3.

The bracket 6 is pivotally connected to housing 3 and is provided for securing the motor to the transom of a boat, not shown. The steering handle 1 extending forwardly from the motor is provided for turning the motor to steer the boat.

The upper end of housing 3 extends generally forwardly and rearwardly to support the front and rear opposed cylinder blocks 8 and crankcase 9 secured between blocks 8. The crankcase 9 carries the Vertical crankshaft I0 which extends downwardly into housing 3 and is connected to drive shaft 2. The flywheel and magneto unit II is mounted on the upper end of crankshaft In above crankcase 9. The fuel tank I 2 is carried above the engine and extends around flywheel unit II. The carburetor l3 connected to fuel tank l2 by means not shown is preferably mounted on one side of crankcase 9 for direct supply thereto of the fuel mixture through the manifold M.

The engine I shown in Fig. l is a four cylinder, two cycle engine of the type employed in most outboard motors and includes an upper and the lowercylinder I5 in each block 8, the pistons l6, and the connecting rods ll. Separate crank throws 18 are arranged for each rod I! so that the opposed upper and lower pairs of cylinders move simultaneously in opposite directions and the two pairs are spaced rotationally on the crankshaft. Cylinder blocks 8 are accordingly offset with respect to the axis of crankshaft II], as shown, to dispose the pistons directly opposite corresponding crank throws. The intake ports I9 admit the fuel mixture carried by the transfer passages 20 from crankcase 9 to cylinders [5.

The exhaust ports 2| of each cylinder l5 open into the exhaust chamber 22 formed in each cylinder block 8. Chambers 22 are closed on the outside by the side cover plates 23 bolted to blocks 8. Each chamber 22 of blocks 8 opens at the bottom into the open upper end of housing 3 to admit the exhaust gases to the latter.

The two planiform, machined upper surfaces of housing 3 are dimensioned to fit the bottom of engine I.

The bolts 24 recessed in the upper body of housing 3 extend upwardly into blocks 8 to secure the blocks and crankcase to the housing and with the gasket 25 disposed between the'crankcase and housing to provide the required tight seal.

The forward block 8 is seated on the higher forward elevation of housing 3 and the crankcase 9 and rear block 8 together fit the lower rear part of the housing.

The two-cylinder, two-cycle alternate firing englne shown in Fig. 3 is comparable to the four cylinder engine previously described and includes the crankcase 26 and cylinder block 8 secured to the top of and supported by the housing 21.

Housing 21 is of cast construction similar to housing 3 but provided with a single planiform surface at its upper end to carry crankcase 26 and block 8. Crankcase 2B is dimensioned to conform to the curved forward upper end of housing 21 and is secured thereto by bolts 24 and pistons 16.

By virtue of the construction of the engines described, numerous component parts and assemblies such as the cooling water circulating connections 30 at the upper end of' drive shaft housings 3 and 2! to register with connections, not shown, for cooling blocks 8 may be employed with either and both engines so that the cost of their manufacture and service maintenance is substantially reduced.

Various embodiments of the invention may be employed within the scope of the accompanying claims.

I claim:

1. In an outboard motor comprising an opposed firing engine and having a pair of offset cylinder blocks of identical construction, an exhaust passage in each block on respectively opposite sides of the engine and opening through the lower face of the blocks, and a drive shaft housing having. a stepped upper end to fit the bottom of the engine and having openings to register with said passages.

2. A drive shaft housing for an opposed firing outboard engine having paired offset cylinder blocks of identical construction and an exhaust passage in each block on respectively opposite sides of the engine and opening through the lower face of the blocks, comprising a hollow cast structure having. a stepped upper end to conform to and lit the lower side of the engine to support the same and having openings adapted to register with said passages.

3. In an outboard motor including a hollow drive shaft housing providing an exhaust cham- 4 her and having two spaced planiform upper surfaces and openings in each surface for receiving exhaust gases, an engine comprising a crankcase, a pair of identical cylinder blocks secured to said crankcase in opposed relation and offset axially of the crankcase, and an exhaust passage in each of said blocks respectively on opposite sides of the engine and opening through the lower face thereof and adapted to register with corresponding openings in said housing.

4. An outboard motor comprising a hollow drive shaft housing providing an exhaust chamber and having two spaced planiform upper surfaces and openings in each surface for receiving exhaust gases, a crankcase, a pair of identical cylinder blocks secured to said crankcase in opposed relation and oifset axially of the crankcase, and an exhaust passage in each of said blocks respectively on opposite sides of the engine and opening through the lower face thereof and adapted to register with corresponding openings in. said housing.

5. In an outboard engine having a crankcase and paired offset cylinder blocks on opposite sides of said crankcase and of identical construction,

said blocks opening downwardly for the exhaust discharge. of the cylinders, a drive shaft housing comprising a hollow cast structure extending beneath. said blocks to support the same and having separate spaced openings at different levels to receive the exhaust directly from the corresponding blocks.

E. CARL KIEKI-IAEFER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,019,856 Strickland Mar. 12, 1912/ 1,252,360 Moore Jan. 1,1918 2,079,571 Johnson May 4, 1.937 2,209,301 Johnson July 23, 1940 2,227,247 Conover Dec. 31, 1940 2,232,160 Blu. et a1. Feb. 18, 1941 2 ,44339'57 I-Ierrington June 22, 1948 

